The vertical type light-emitting diodes (LEDs) become a popular choice to light-emitting diodes package for its simple design, high power, high efficiency, and long life-time. To optimize the heat dispersion, the light-emitting diodes are usually attached to the metal substrate by bonding technology, or by electroplating technology to evaporate metal film on the epitaxy layers. However, due to the difference of the thermal expansion coefficients of materials, the light-emitting diode wafer often cracks during the manufacturing which influences the wafer life-time indirectly.
Generally, a metal matrix composite material is produced by fusing materials having low thermal expansion coefficient with metals having high thermal conductivity in a high temperature process to achieve high thermal conductivity and low thermal expansion coefficient. However, the high temperature process does not suit for light-emitting diode chip manufacturing. Recently, the composite electroplating has developed vigorously. The various kinds of composite material compositions have been developed and used in the surface coating for the purpose of wear-resisting and waterproof. Taking the nickel-silicon carbide composite electroplating as an example, the principle is to precipitate and co-coat nickel and silicon carbide on the substrate by the electroplating solution containing the nickel ions with the inert silicon carbide particles suspended therein. When there is stress existed between the composite electroplating layer and the substrate, the material(s) selection of the interfacial layer, the number of layers, and the thickness of each layer are important topics for considering.